Injection of solids into a high pressure slurry stream

ABSTRACT

An apparatus for multiple injection of slurry from a plurality of mine faces or other slurry sources into a slurry line comprises a unique method and apparatus for connecting each slurry injection point to the main slurry line by using a vortex junction apparatus. The vortex junction apparatus provides a means for passing the slurry from one junction point to the next junction point and at the same time provides a means for merging slurry from each injection point into the main slurry line. The junction apparatus also provides a source of water for each injection point, thus eliminating the need for a separate source of water. One embodiment provides for a junction where the main and branch slurry lines are at nearly the same pressure while a second embodiment provides for a junction where the branch slurry line is at a substantially lower pressure than the main slurry line.

RELATED APPLICATIONS

This application is a continuation-in-part application of U.S. Ser. No.439,670 filed Nov. 8, 1982, entitled "Injection of Solids Into A HighPressure Slurry Stream" by Jeffrey L Beck and Ahmed A. El-Saie, now U.S.Pat. No. 4,453,864.

DISCUSSION OF THE PRIOR ART

The best prior art known to Applicants are applications U.S. Ser. No.231,637 filed Feb. 5, 1981, and titled "Dredging Apparatus", now U.S.Pat. No. 4,409,746, which discloses a vortex chamber being used both asa dredging pump and as a lift apparatus; U.S. Ser. No. 218,857, now U.S.Pat. No. 4,449,862, filed Dec. 22, 1980, and titled "Vortex InjectionMethod and Apparatus" which discloses a vortex chamber being used as alift apparatus; and U.S. Ser. No. 264,917, now U.S. Pat. No. 4,444,229,filed May 18, 1981, which discloses vortex apparatus used as a slurryconcentrator in an underground mine, all of the above applications tothe same inventor, Jeffrey L Beck, and assigned to the same assignee asthis invention.

U.S. Pat. No. 4,143,922 issued Mar. 13, 1979, to William T. Sweeney andtitled "Method of Multiple Point Injection for Slurry Pipeline"discloses one approach toward producing at a plurality of mine faces andinjecting the slurry from each mine face into a main or single slurryline without the use of a central sump as normally required in anunderground mine. For example, the patent includes means to accommodatethe excess material being injected into the main slurry line bydetecting the flow of slurry downstream from each slurry injection pointand water injection point and varying the amount of injected water alongwith changes in pipe diameter to maintain proper velocities in theslurry pipeline at each point along the line. In the Sweeney patent, themaintenance of velocity in the pipeline requires a complex controlsystem caused by the necessity for measuring the flow rate and adjustingthe water injected into the slurry line at each slurry injection pointin order to compensate for the variations in slurry injected from eachmine face into its corresponding injection point.

BRIEF DESCRIPTION OF THE INVENTION

Unlike the parallel-type connection of each mine face across the mainslurry line and water line, respectively, this invention comprises aseries coupling of a vortex junction apparatus for each mine face orother source of slurry following the first mine face. The main line iscoupled to the high pressure inlet and from the high pressure outlet tothe next vortex junction high pressure inlet for each successive mineface. Each mine face or other slurry source receives its water from thelow pressure outlet and injects its slurry into the branch slurry inlet.Booster pumps can be installed where necessary. Flow control can beadded where desired to maintain the velocity constant by controlling thelow pressure water leaving each vortex junction as well as water coupleddirectly across the first injection point.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a plan view of a mine layout illustrating a slurry pipelinesystem carrying out the method of the invention;

FIG. 2 is a perspective view of the vortex junction showing the vortexchamber, the connections of the pipes to and from the chamber and thecoupling to an optional booster pump; and

FIG. 3 is a perspective view of a modified apparatus illustrated in FIG.2.

DETAILED DESCRIPTION OF THE INVENTION

Ordinarily, when coal is mined at a plurality of mine faces or othersources such as a surface mine, phosphate mining location and the likeusing a slurry system, the coal or mineral is conveyed either with aslurry system or by a conveyor to a central sump where it is dumped andthen subsequently removed by a suction pump where it is transferred to ahoist or "main line" system for removal from the mine. Where the coal ormineral at each injection point is transferred by a slurry system, thecoal or mineral can be dumped into a small portable sump where it ismixed with water and conveyed to the central sump, or it can beconveyed, as in the case of a longwall operation, to a fixed sump whereit is mixed with water and conveyed to the central sump. One form of acentral sump is illustrated in U.S. Pat. No. 4,143,921 issued Mar. 13,1979, to W. T. Sweeney titled "Slurry Input for Multiple Feed Sump".These sumps are generally very large and expensive to build and requirea substantial amount of maintenance along with control circuitry tooperate them. It would simplify a slurry mining technique to eliminatethe central sump and its associated equipment by the substitution of anapparatus which would permit injection of the coal from several minefaces directly into a single mine slurry line as the coal is produced.Such a system was first disclosed in the U.S. patent to W. T. Sweeney,U.S. Pat. No. 4,143,922, issued Mar. 13, 1979, entitled "Method ofMultiple Point Injection for Slurry Pipelines." This patent describes aparallel system of operating a slurry injection system and functions byaccepting fluid from a water line which runs to all of the mine faceswhere the water is injected into the portable sump and mixed with thecoal to form a slurry. The slurry is then injected into a branch slurryline at each of the mine faces. The slurry from each mine face thenenters a main slurry line at junction points along the main slurry line.In order to maintain adequate velocity in the main slurry line, acoupling is provided at each of the junction points between the waterline and the slurry line which is valve controlled by a centralcomputer. When slurry is being injected, water flow is reduced orstopped between the water line and the slurry line in accordance withdetected flow through the main slurry line at that point. The systemmust require extremely careful flow control in order to maintain propervelocities in the main slurry line and, furthermore, does provide ahigher percentage of water in this line in order to maintain the propervelocity regulation. The system also requires changes in the slurry linediameter to accommodate the increased fluid volume.

The aforementioned system is substantially improved in the inventiondisclosed herein where the injection points are each connected in serieswith the main slurry line rather than in parallel between main water andslurry line as in the previously described patents. Furthermore, themain slurry line diameter can remain the same throughout the minethereby making movement of slurry injection locations much easier.

Referring to all of the figures but in particular to FIG. 1, a seriesconnected injection system is disclosed which comprises a source ofwater 10 connected by a means of pipe 11 through a blocking valve 12 anda subsequent pipe 13 to a first injection point 14 which generallyincludes a portable sump, but could be a fixed sump, for mixing coal orother mineral being mined with the fluids. The injection point will alsonormally include a pump for removing the slurry from the sump. One formof injection point is illustrated in U.S. Pat. No. 3,845,990 by David L.McCain, titled "Slurry Hopper System" and assigned to the same assigneeas this invention. The slurry is formed at the injection point, leavesby means of pipe 15 through a blocking valve 16 to the main slurry line17 which is then coupled to the first vortex junction 81 which includesa vortex chamber 18. One form of a vortex junction is described as aslurry concentrator in the previously mentioned U.S. patent applicationSer. No. 264,917 to Jeffrey L. Beck and will not be further describedhere; however, a brief description of its operation will be furtherdescribed in FIG. 2. A second form of a vortex junction is completelydescribed as a vortex injection apparatus in the previously mentionedpatent application Ser. No. 218,857 also to Jeffrey L Beck and will notbe further described here; however, a brief description of its operationwill be further described in FIG. 3. Each vortex junction has a highpressure inlet 19, a high pressure outlet 20, a low pressure outlet 21,and a second inlet 22 which may be high pressure as will be illustratedin FIG. 2 or a low pressure as illustrated in FIG. 3. The high pressureoutlet 20 is connected to the next succeeding portion of main slurryline 17. The low pressure outlet product will comprise mainly water andis coupled through a blocking valve 23 to the inlet 24 of a booster pump25. The outlet 26 of booster pump 25 is coupled through a pipe 13a tothe second injection point 27. The outlet of the second injection point27 is coupled through slurry line 15a through a blocking valve 28 to theinlet 22 of vortex chamber 18. There can be any number of subsequentjunction points as illustrated by the arrow 30. Since each subsequentjunction point 30 will be subsequently identical to the previousjunction point, there will be no need to describe each further junctionpoint. As required, additional booster pumps 31 can be mounted alongmain slurry line 17 to increase the pressure of the slurry in line 17.Main slurry line 17 is eventually coupled to lift system 32 which willtransport the slurry outside the mine and to a separate facility whichremoves the water from the slurry and processes the coal or othermaterial in the usual manner for the mine. In order to assure the propervelocity through the system, an autoselect controller 33 (which may alsobe a computer) has at least one flow meter 34, which measures thevelocity through main slurry line 17 at a location between the first andsecond injection points 14 and 27, respectively, and transfers theinformation through means 37, to autoselect controller 33. Adensitometer 36 attached to slurry line 17 communicates its outputthrough a means 39 to an input of autoselect controller 33. Thecontroller processes the inputs and applies an output through means 40to a control valve 43.

Operation

For the initial startup procedure, valves such as 12 and 16 and 23 and28 will be closed and valve 43 will be opened. Water will then besupplied from water source 10 down pipe 11 through control valve 43 andinto main slurry line 17. Vortex chamber 18 will be filled along withall of main slurry line 17 and each succeeding vortex chamber will befilled as well as all booster pumps such as 31 to lift system 32. Oncethe main slurry line and its components are filled, blocking valves 12and 16 are opened and water is supplied to injection point 14. Thenblocking valves 23 and 28 are opened supplying water to injection point27. Each succeeding injection point that is to be used is similarlyfilled with water. The autoselect controller 33 has two main functionsin the system. First, it must always, through minimum controlled closureof valve 43, maintain a predetermined minimum flow in slurry line 17. Ifa minimum flow is not maintained, then the solids will settle out of thewater carrier fluids causing the line to plug or become less efficient,and, second, it must maintain a predetermined maximum density in theslurry line 17. Too high a density will also cause a reduction in flowand possible plugging. Ideally, the system, then, should have at leastone flow meter near the first injection point and at least one densitymeter following the last injection point. Other flow meters, such as 35and coupling means 38, or densitometers may be included at variouspoints in the line when better control is considered necessary. Oncecoal or other mineral has begun to be added to injection point 14, forexample, some of the volume of water will be replaced with coal ormineral. Since the same volume of water is pumped through pipes 13 and15, an increase in flow will be detected at the line flow meter 34 whichwill be connected through means 37 to autoselect controller 33. Thiscontroller will then communicate the proper response through means 40 tocontrol valve 43 to reduce or increase the flow of water from line 11 tomain slurry line 17 resulting in a change in flow in line 17 andadjusting the flow to a predetermined set amount. If coal or mineral isbeing added, for example, to injection point 27, the coal or mineralwill replace part of the water in line 15a. Since most injection pointscontain a fluid level monitoring apparatus on the sump, a valve willclose down the fluids coming from pipe 13a in order to maintain the sumpat a constant level. The coal or mineral being added to line 15a willcause an increase in the density sensed by densitometer 36 andcommunicated to autoselect controller 33 via line 39. A signal will becommunicated through means 40 to control valve 43 in the event thedensity exceeds a predetermined maximum value, thereby increasing thetotal flow through the system. Each succeeding injection point willfunction in substantially the same way as the two injection points abovedescribed with any density change being monitored by densitometer 36 andtransferred by means 39 to autoselect controller 33. In the systemillustrated booster pumps 24 and 31 have been included. It is obvious insome conditions that neither booster pump may be needed. The boosterpump will be required for line 13a, for example, if pressure problemsrequire additional pressure in the line.

It can be seen from the above description that the series connectedcircuit illustrates an extremely easy startup and an extremely easy wayto monitor and control injection of solids at the various stations.

Referring to FIG. 2, a perspective view of the vortex junction portionof the apparatus of FIG. 1 is illustrated showing a vortex chamber 18having the main slurry line 17 coupled to the input 19 and an output 20coupled to the succeeding portion of main slurry line 17. The lowpressure outlet 21 is coupled through valve 23 to the inlet 24 of anoptional booster pump 25. Its outlet 26 is coupled to the pipe 13 whichcommunicates the fluids to the injection point as illustrated in FIG. 1.The return pipe 15 from the injection point passes through valve 28 andto an inlet 27. The configuration illustrated in FIG. 2 shows the vortexchamber mounted so that its axis is horizontal. It is obvious this wouldnormally require more space than if it were vertical. The system willfunction either way just as well. In the case where the axis ishorizontal it is preferred to have outlet 20 above inlet 19 since anemergency shutdown may cause vortex chamber 18 to fill with materialwhich would settle and make startup difficult. It is also preferred tohave inlet 19 at the bottom so that the high pressure in line 17 candislodge any settled material.

The vortex junction shown in FIG. 2 is very similar to the previouslymentioned slurry concentrator disclosed in U.S. patent application Ser.No. 264,917 to Jeffrey L. Beck, the only difference being the additionof a second tangential inlet 22 at the perimeter of vortex chamber 18.

A second embodiment of the apparatus is illustrated in FIG. 3. In thisembodiment pipe 15 is coupled through valve 28 to an input 22 which isat the axis of vortex chamber 18. A concentric pipe 50 is mounted aroundinlet 22 and accommodates the low pressure outlet 21 of the vortexchamber which is coupled through valve 23 to inlet 24 of centrifugalpump 25. In order to make the system illustrated in FIG. 3 work, fluidmust be transferred continuously from the center to the periphery of thevortex or else the lower pressure vortex will not form. In order toaccomplish this, water is communicated through an inlet 29 of pipe 41 toa control valve 42 and from there through pipe 48 to a junction 49 whichis coupled to main slurry line 17 at the input 19 of vortex chamber 18or directly into vortex chamber 18 through a second tangential inlet(not shown). A pressure transducer port 44 is mounted at pipe 51 and iscoupled to pressure transducer 45 which is used in conjunction with ananalog or digital controller and control valve 42 to regulate thepressure in pipe 51. The output of pressure transducer 45 is coupledthrough means 46 to controller 60. A controller 60 has an output coupledthrough means 61 to the control 47 to valve 42. If control of the flowrate in pipe 15 is desired, a flow meter 71 can be installed in pipe 15and its output connected through a means 46a to controller 60. Pressuretransducer 45 can be eliminated in this case.

The system of FIG. 3 operates in much the same manner as the apparatusdescribed in FIGS. 1 and 2. The only difference is that the outlet fromvortex chamber 18 forms a concentric pipe around inlet 22 and inlet 22,rather than being a high pressure inlet, is a low pressure inlet sinceit is entering near the center of vortex chamber 18. Inlet 22 can alsobe coaxially positioned on the opposite side of vortex chamber 18. Inorder to control the flow of fluids from the center of the vortex to theperiphery through pipes 41 and 48, the pressure is continually monitoredat port 44 through pressure transducer 45 which response is communicatedthrough output 46, controller 60 and through controller output 61 tovalve control 47. Thus every pressure variation in pipe 51 will cause achange in the setting of the valve 42 and result in an alteration in theamount of fluid transferred from pipe 13 to pipe 17. It is also obviousthat other means can provide the signal for controlling the flow offluids from pump 25 to inlet 19 such as a differential pressuretransmitter for measuring differential pressure between pipes 51 and 48or a flow meter in pipe 51 which have their output coupled to controller60, for example.

Conclusions

An extremely efficient series system has been disclosed for operating aplurality of injection points using a vortex junction to couple eachinjection point succeeding the first injection point to the main slurryline. The vortex junction apparatus provides an unusual means tofacilitate ease in injecting slurry into the main slurry line and at thesame time separate fluid from the slurry for recycling to the injectionpoint. In this configuration no separate pipe need be run through themine for the purpose of carrying fluid to each injection point in themine. The lack of such pipe will not only provide additional space inthe mine but also reduce the cost of installation drastically. Thecontrol circuits for maintaining a proper flow in the main slurry lineare simple and easy to function since the only control responding to achange in flow is a bypass valve which transfers water from the sourceof water to the main slurry line. Since it is not necessary to changethe main line pipe diameter at each junction point, the ease with whichjunction points can be relocated along the main line will be muchgreater than in a parallel type system, which requires a change in themain slurry line diameter at each junction point. Relocation of thejunction points is necessary as mining progresses.

The system has been specifically described for use in an undergroundcoal mine. It is obvious that the system can be used at any locationeither underground or on the surface. It is further obvious that anymineral or material can be injected into the system including fluidother than water.

It is also obvious that changes can be made in the application and stillbe within the spirit and scope of the invention as disclosed in thespecification and appended claims.

What is claimed is:
 1. A multipoint injection system for first andsucceeding slurry sources, said system having a source of waterconnected to said first slurry source with a slurry from said firstslurry source coupled to a main slurry line, controllable bypass valvemeans coupled between said source of water and said main slurry line,vortex junction apparatus at a location servicing each succeeding slurrysource, said vortex junction apparatus having a high pressure inlet anda high pressure outlet, a low pressure outlet and a slurry inlet, meanscoupling each vortex junction apparatus in series with said highpressure inlet and said high pressure outlet coupled in series with saidmain slurry line, and means coupling said last vortex high pressureoutlet to a transfer system, means for coupling each of said lowpressure outlets to said corresponding slurry source for supplyingfluids to said slurry source and means for coupling slurry from saidslurry source to said corresponding vortex junction apparatus slurryinput, flow measuring means coupled to said main slurry line from saidfirst slurry source and generating an output, means accepting saidoutput and generating a control signal to said bypass control valve formaintaining said flow in said main slurry line at a predetermined value.2. Apparatus as described in claim 1 wherein the slurry output from eachsucceeding slurry source is coupled into a vortex junction apparatushaving a high pressure slurry inlet.
 3. Apparatus as described in claim1 wherein the slurry output from each succeeding slurry source iscoupled into a vortex junction apparatus having a low pressure slurryinlet and including fluid feedback means from said low pressure outletto said high pressure inlet.
 4. Apparatus as described in claim 1, 2 or3 wherein a densitometer is coupled to said main slurry line followingsaid last vortex junction apparatus, and having an output communicatingwith said means for accepting said flow measuring means output. 5.Apparatus as described in claim 1, 2 or 3 wherein a booster pump havingan outlet and an inlet is incorporated with said booster pump having itsinlet connected to said low pressure outlet of said vortex injectionapparatus and its outlet coupled to said slurry source.
 6. Apparatus asdescribed in claim 3 including a valve having a control means, in saidfluid feedback means and pressure sensing means in said low pressureoutlet coupled to said control means for regulating the fluid flowthrough said fluid feedback means.
 7. Apparatus as described in claim 3including a flow measuring apparatus in said means for coupling saidslurry from said mine face to said corresponding vortex junctionapparatus input for regulating the fluid flow through said fluidfeedback means.